Our general objective is to study the development and inheritance of cellular organelles using Euglena as a convenient research organism. Specific objectives include: an investigation of the blue-light receptor system controlling the non-plastid contributions to chloroplast development including action spectra for processes which are photocontrolled in a mutant lacking the protochlorophyll(ide) system and studies of the responsible pigment in vivo and in cell extracts; to explore the mitochondrial contribution to plastid development; to study the assembly of plastid membranes using specific inhibitors of the process and to study the formation of specific membrane constituents; a study of the relation of ribulose diphosphate carboxylase to pyrenoid differentiation and to continue our work on the loss of plastid forming units and their DNA from organisms dividing in the presence of bleaching agents.